2007 World Wealth Report

The number of HNWIs in the world increased 8.3 percent in 2006 to 9.5 million and the number of ultra high net worth individuals (Ultra-HNWIs2) grew by 11.3 percent to 94,970.

HNWI financial wealth is expected to reach US$51.6 trillion by 2011, growing at an annual rate of 6.8%.

USA has 2.92 million HNWI ($1 million in liquid assets)
The wealth report is a pdf that is at this location. You need to register to download it

2006 2005 2004 Wealth Amount
5 3 2 US$30B+ Forbes list (which mainly catches owners
67 49 32 US$10B+ of public assets, can underestimate some
167 124 102 US$5B+ like CTO of Cisco, who may be billionaire
946 793 691 US$1B+ from cisco stock + large startup positions)
9400 8200 7500 US$160M+ (my own estimate)
95,000 85400 77500 US$30M+ (UHNW, ultra high net worth class)
(e)930,000 820000 745000 US$5 to 30M
8.6M 7.8M 7.4M US$1-5M Global number, US number 33% (2.6 million)
9.5M 8.7M 8.2M US$1M+ Global number, US number 33% ( 2.6 million)
~26M ~24M ~22M US$500K-1M doesn’t include primary residence, (estimate)

For the 5 million net worth level, estimates for household net worth at this level or higher is about 1.14 million (Spectrem) in the US alone. So about 3 million worldwide.

Global direct real estate transaction volumes reached US$682 billion in 2006, up 38 percent from 2005.

FURTHER READING:
Sources of wealth for the rich and how much money it takes to be rich